Collapsible water tank for medical radiation therapy



FIG. 1 is a perspective view of a collapsible water tank showing the top, the front, and one side view of my new design;

FIG. 2 is a right elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a bottom plan view thereof; and,

FIG. 5 is a top plan view thereof. 

The ornamental design for a collapsible water tank for medical radiation therapy, as shown and described. 